Affinity-purified adenylate cyclase (AC) of Bordetella pertussis, free of contaminating pertussis toxin, was demonstrated to have biological effects on human polymorphonuclear leukocytes (PMN). AC at doses of 25 and 50 pg/ml increased intracellular cAMP levels in the phagocytes 7.6to 23.5-fold, respectively, above basal levels. AC inhibited PMN chemiluminescence, chemotaxis, and superoxide production in a dose-dependent manner. The 50% inhibitory dose for chemotaxis and chemiluminescence was

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... 5 .Lg/ml; for superoxide generation it was 71.0 ,ug/ml. Although these PMN metabolic functions were impaired, no effect on phagocytic activity was observed. LITERATURE CITED